The selection of pharmaceutically acceptable salts is a critical step in the process for researching and developing new medicines. This is because salts of certain medicines can often be important determinants of ease of preparation of medicine raw materials, solubility, stability during distribution and storage, ease of formulation and pharmacokinetic properties.
The production of various kinds of salts can be a means of changing the physiochemical and biological properties of the medicines without altering the chemical structure of the specific medicines. Upon selecting a preferred salt, the properties of many salts must be considered. For example, it can be taken into consideration depending on the environment and the situation where various factors such as ease of production, stability, solubility, and/or hygroscopicity of salt are used.
In particular, there is a continuing need for drug formulations that exhibit better bioavailability or better stability, and thus continuous research for novel salts or purer salts of existing medicine molecules has been conducted.
Thus, the present inventors have found that a novel acid addition salt of 1-(5-(2,4-difluorophenyl)-1-((3-fluorophenyl)sulfonyl)-4-methoxy-1H-pyrrol-3-yl)-N-methylmethanamine which is a new active medicinal substance can be prepared and they can be pharmaceutically used based on their physicochemical properties and stabilities, thereby completing the present invention.